Project
ASME HPVC
Human-Powered Vehicle Design
Guacamaya
HPVC Design
Aerodynamic evaluation and vehicle-level design integration for a front-wheel-drive human-powered competition trike.
Aerodynamics Lead
Guacamaya human-powered vehicle design
Vehicle
Guacamaya
Primary Role
Aerodynamics Lead
Main Tool
ANSYS Workbench
The Objective
Was the Fairing Worth Building?
My primary responsibility was to determine whether an aerodynamic fairing would provide enough total vehicle benefit to justify its development.
The evaluation considered more than drag reduction. The fairing would also introduce additional weight, tooling, material cost, manufacturing lead time, visibility constraints, and integration requirements.
My Contribution
Aerodynamics and Integration
- ●Evaluated fairing geometry and aerodynamic performance using ANSYS CFD.
- ●Compared aerodynamic improvement against manufacturing and system-integration demands.
- ●Supported steering, braking, and drivetrain packaging around the front axle.
- ●Communicated the design tradeoff and recommendation to the larger HPVC team.
Engineering Method
From Concept to Design Decision
The analysis followed a staged process that connected geometry, CFD validation, aerodynamic performance, and practical manufacturability.
STEP 01
Define the performance target
Evaluate whether an aerodynamic fairing could reduce drag enough to justify its additional weight, manufacturing effort, cost, and vehicle-integration requirements.
STEP 02
Develop the fairing geometry
Create a streamlined fairing concept inspired by a teardrop profile while reducing frontal area and maintaining coverage of the rider and vehicle.
STEP 03
Validate the CFD method
Analyze a sphere with a known drag-coefficient range before applying the same CFD workflow to the fairing geometry.
STEP 04
Evaluate the full tradeoff
Compare the predicted aerodynamic performance against manufacturing complexity, material requirements, development time, and integration risk.
CFD Evaluation
Aerodynamic Analysis
The ANSYS workflow used a k-ε turbulence model, a no-slip boundary condition, and a 25 mph inlet velocity. A sphere with a known drag range was analyzed first to validate the methodology.
Simulation Velocity
11.18 m/s
Equivalent to 25 mph
Target Drag Coefficient
< 0.44
Team design specification
Predicted Fairing Cd
0.35
Reported CFD result
Validation Error
6.41%
Sphere validation case
Design Decision
Do Not Proceed
The proposed fairing was not advanced into manufacturing for the final competition vehicle.
Engineering Tradeoff
Performance Was Only One Part of the Decision
The CFD result indicated that the fairing could meet the aerodynamic target. However, an engineering decision must consider the entire system rather than one performance metric.
The expected benefit was weighed against added mass, manufacturing uncertainty, material and tooling requirements, schedule limitations, subsystem clearance, and limited team resources. The team therefore redirected effort toward systems with greater immediate impact on vehicle reliability and competition readiness.
Cross-Functional Design
Front-Axle System Integration
After the aerodynamic evaluation, I supported the integration of steering, braking, and power-transmission systems located around the front axle.
Front-Wheel-Drive Packaging
The front axle needed to accommodate steering, braking, drivetrain, and wheel components within the same constrained region.
Steering-System Revision
Front-wheel-drive integration led the team to reconsider the original steering layout and adopt a more compact under-seat mechanism.
Fairing Clearance
The aerodynamic body needed to avoid interference with steering movement, rider visibility, wheel travel, and subsystem maintenance.
Team Design Validation
Rollover-Protection and Structural Analysis
The structural analyses below were completed as part of the overall HPVC team effort. My primary role was aerodynamics, but these results provide important context for the complete vehicle design and its competition requirements.
RPS Top Load
0.58 cm
Maximum deformation
Safety factor: 1.7
RPS Side Load
0.0054 cm
Maximum deformation
Safety factor: 11.6
Weight Distribution
0.083 cm
Maximum deformation
Safety factor: 2.3
Design Gallery
Vehicle and Subsystem Development
Reflection
Lessons Learned
Engineering value is broader than performance
A component can produce a measurable performance improvement and still not justify its added weight, cost, manufacturing effort, or development risk.
Validate the analysis workflow
Comparing the CFD method against a body with a known drag-coefficient range increased confidence before evaluating the custom geometry.
Subsystems cannot be designed independently
The fairing, steering, drivetrain, brakes, wheels, and frame competed for the same space and required continuous cross-team coordination.
Not building a feature can be the correct result
The purpose of analysis is to guide decisions. Eliminating a feature that does not provide sufficient total-system value is a successful engineering outcome.
Technical Documentation
HPVC Critical Design Review
View the complete team report for detailed design selection, structural analysis, aerodynamic methodology, subsystem calculations, testing plans, and competition requirements.